In a planet gear carrier used in a vehicle transmission, lubrication is needed for the needle bearings and other parts. If lubricant can leak out to the point where the parts lose their lubrication, then problems arise. Therefore, the need arises for an oil shield that will provide complete sealing to capture the lubricant and prevent leakage.
An example of a planet gear carrier with an oil shield is disclosed in European patent 0 274 874. In this planet gear carrier arrangement, the oil shield that is secured in a region radially outside the planet wheel spindle to a side wall of the planet gear carrier is formed from a simple sheet metal pressing with a radial flange part and a conical capture part, the oil shield being fixed at its flange part by means of a snap ring or locking ring which also serves to retain the planet wheel spindle.
This arrangement and form of an oil shield suffers from the disadvantage that a considerable amount of the captured lubricant can be lost radially across its flange part and the fastening through the retaining ring, since the retaining ring with a radial opening in it does not provide complete sealing. Lubricating problems can then arise from lack of lubricant, requiring the whole of the lubricant captured by the oil shield to be passed to the planet wheel bearings.
In an attempt to overcome these problems, an oil shield was made up of a radial flange part and a conical capture part and secured by a snap ring, the outer circumference of the flange part being provided with an axially vulcanized-on seal of elastic material which formed a seal relative to the inner end region of a side wall, formed as a drum, of a planet gear carrier. However, the manufacturing operation for vulcanizing the seal on to the sheet metal oil shield is relatively troublesome and costly, and also the groove required for the retention of the oil shield by means of a snap ring requires an additional machining step on the drum-shaped side wall of the planet gear carrier.